Receive the latest events updates in your inbox

WASHINGTON - MAY 8: Spectators gather to watch the illumination of the Washington National Cathedral by Swiss lighting artist Gerry Hofstetter May 8, 2008 in Washington, DC. For three nights, Hofstetter will illuminate the Cathedral with a series of slides titled "Lighting to Unite" in celebration of the Cathedral's centennial. (Photo by Win McNamee/Getty Images)

Don’t be surprised if things are a bit dimmer than usual this Saturday night.

Environmentally conscious folks around the world will be taking part in the annual “Earth Hour.” The Washington-based World Wildlife Fund organizes the event.

The organization is asking people to dim the lights for an hour starting at 8:30 p.m. local time in an effort to highlight the threat of climate change.

In the District, the D.C. government says it will turn off nonessential lighting at city hall, the Frank D. Reeves Center for Municipal Affairs and One Judiciary Square. Lights also will go out at the D.C. Department of the Environment and D.C. public schools offices in northeast Washington.

In addition, many hotels and other buildings are dimming their lights, including the Smithsonian Castle the Washington National Cathedral.

"As a community of faith, we recognize our planet as a sacred gift from God to enjoy, protect, and ultimately, pass on to the generations that follow," said Cathedral Dean Samuel T. Lloyd III.

A spokesman for Maryland Gov. Martin O’Malley said the governor’s residence in Annapolis will be dark as well. The town of Poolesville, Md., and the National Aquarium in Baltimore will also get in on the no lights action.

According to Earth Hour's Web site, the event started three years ago and goes around the Earth. Buildings in some 4,000 cities in more than 120 countries are expected to unplug to reduce energy consumption and draw attention to the dangers of climate change, according to organizers.